Process of desulfurizing petroleum-oils



E. B. COBB.

PROCESS OF DESULFURIZING PETROLEUM OILS.

APPLICATION FILED MAR.13,1919- Q Patented Nov. 2, 1920.

2 SHEETS-SHEET 1.

I 7 Wflfr E. B. COBB.

PROCESS OF DESULFURIZING PETROLEUM OILS.

' APPLICATION FILED MAR-13,1919- 1557224. Patented Nov. 2,1920.

INVENTOR.

2 SHEETS-SHEET 2.

WITNESS:

Wm a;

ATTORNEY.

UNITED STA-res PATENT OFFICE.

ERNEST B. CODE-OF JERSEY crrr, N W JERSEY, ASSIGNOR 'ro STANDARD on.

. oomranr, A CORPORATION or NEW JERSEY.

rnoc ss 0E nEsU URrzIne PETROLEUM-OILS.

Application filed March 13,

To aZZ whom it may concern:

Be it known that l, ERNEsrB. Come, a citizen of the United States, residing at Jersey City, in the county of Hudson and State of New Jersey, have invented certain new and useful Improvements'in Processes of Desulfurizing Petroleum-Oils, of which the following is a specification.

My invention relates to "new and useful improvements in processes for the removal of elementary sulfur. from petroleum oils: and my present application is a division, in part, of my prior applicittion, Serial No. 50,177, which was filed in the Patent Oflice on or about September 11, 1915, Patent No. 1,300,816, which was,issued April 15, 1919.

flBy-elementary sulfur, I 'mean; that sulfur which exists in the oil in its elementary forms, such as brimstone, flowers of sulfur, and all other modifications of elementary sulfur held' in physical solution in the oil. The'invention is applicable to, and covers the removal of elementary sulfur primarily existing as such in the oil, and also elementary sulfur resulting from acid treatment of the oils, and other, processes of refining and chemical treatment. The presence of" elementary sulfur in petroleum oils may be ascertained by first testing the-oil by any of the well-known tests for hydrogen sulfid or sulfurated hydrogen (H S) and removing the same, if any be present, by any of the well-known processes for this pur-- pose, after whicha piece of bright copper or silver is immersed in the oil freed of sulfu'reted hydrogen (H S), and the oil heated; if any elementary sulfur is present it' will act to tarnish or blacken the copper or silver. The removalofsulfureted hydro gen from the test oil is a necessary preliminary, because it also darkens copper and silver. But in the treatment ofthe main body of oil, ashereinafter described, it" is unneo'essary'to remove -the sulfureted hydrogen by preliminary treatment. I .My'p'resent application relates to:the removal of elementary sulfur existing in petroleum oils, either primarily, oras th result of treatments or reaction with 6 her compounds or elements, preferably under agitation, by treating the oil with hydrooxids. of either, the alkali metals, 'partiou-. larly sodium, orthe alkaline earth metals, particularly calcium, and with hydrogen sulfid. The hydroxids form with the hydro- Specification of Letters Patent. I

Patented Nov. 2, 1920. 1919. Serial No. 282,287.

gen sulfid monosulfids, and possibly other sulfids. It isa-well known that higher sulfids of these metals, such as sodium and calclum exist, and the chemical action in using the sulfids 'resultin from the .reaction between the hydroxlds and the hydrogen sulfid, as contemplated by my invention, s to cause removal of the elementary sulfur apparently by simple addition, the sulfurcombining with the low sulfid of the alkali metal or alkaline earth metal to produce higher sulfids.

, My present invention, therefore, contemplates the treatment of. the oil with a hydroxid of either an alkali metal or an al lgline earth metal, and with hydrogen sulclude the .hydroxids of the alkali metalgroup, including ammonia, potassium, sodium, and other metals of said group. I11 practice, I prefer to employ sodium, as it is the most abundant, of the metals of this group, and lower in price. Whether the oil 1s to be treated with hydroxids of the alkali metals andhydrogen sulfid, or whether it is In referring to alkaline hydroxids, I into be treated with hydroxide of the alkaline I earth metals and hydrogen sulfid, depends to some extent upon the character of the oil to be treated, the character of the finished products, and the individual preference. Bv alkaline hydroxids, as used herein, and

in the appended claims, I include the hygroup, and the carried out, Figure 1 is a view in elevation,

partially in section, of an apparatus partic-' ul'arlyuseful in the practice of my inven tion when employing hydroxids of the alkali metal group, and hydrogen sulfid,'and Fig. 2 is a view similarto Flg. 1, illustrating an apparatus suitable for carrying out apparatus which have been.

my invention when employing hydroxids of the alkaline earth metals, and hydrogen sulfid,

I will first describe the apparatus illustrated in Fig. 1 of the drawings, and then I adapted to receive the oil to be treated, and having a conical bottom 2 and a domeshaped top or cover 3, provided with explosion doors 31. .The conical shaped bottom 2 is provided at its apex with an outlet pipe 4 having a valve 5 at its lowermost ortion through whichpipe the contents of t e cylinder may be flowed when the valve'is open, as will behereinafter described.

6 designates a receptacle or tank of any suitable construction adapted to receive the supply of chemical with which the oil is to be treated, said tank being connected by an outlet pipe 7 with the inlet side of a circulating pump 8, said pipe containing a valve 9 for cutting off and establishing flow through the same to the pump. Connected to the outlet side of the pump is a feed pipe 10 extending upward from the pump and provided with a horizontal portion 11 entering the side of the cylinder 1 and provided at its end within the cylinder, with a depending pipe 12 having its lower end closed, but its sides perforated so as to distribute the chemical in fine streams within the cylinder to insure proper admixture of the same with the oil contents of the cylinder. The pipe 7 is connected at a point between the valve 9 and the inlet of the pump to one end ,of a pipe 13, the opposite end of which is connected to the pipe 4 at a point above the valve 5, heretofore mentioned. The pipe 13 is provided with controlling valves 13 and 14 by means of which communication through said pipe 13 to the pump is controlled. Connected at one end to the pipe 4 between the valve 5 and the point of connection of the pipe ,13 is an outlet or drain pipe 15 provided with an'outl et neck 16 discharging into the tank 6', heretofore de-. scribed. The pipe 15 is provided with a controlling valve. 17. for controlling flow therethrough. Y

18 designates a steam inlet pipe entering through the dome 3 and 'provided-with a depending outlet portion 19 by means of which live steaminay be admitted to the illterior of the cylinder, an air inlet pipe 20 being connected with pipe 18 and provided with a valve 21 fora purpose to be presently described. The pipe 18 maybe provided with a valve 22 for controlling the flow of the'steam to the same to the interior of the cylinder, said pipe 20 being connected with the pipe 18 between theeva lve 22and the outlet end of said pipe 18. Also connected to the steam pipe 18 is a' pipe 23 leading to a closed heating coil 24, of any suitable form,

upper portion thereof, and extending to a point preferably within the area of the coneshaped bottom. The treated oil may be withdrawn from the cylinder through an outlet pipe 28, controlled by a valve 29, said pipe being located adjacent to, but above, the lowermost portion of the cone-shaped bottom. The hydrogen sulfid is introduced to the oil from any suitable source through a pipe 30, the end of which extends a short distance, for example, about a foot beneath the surface of the oil to be treated. The pipe 30 is provided with a suitable valve 30. I do not desire to be limited in any way to an apparatus such as described, having only described the samein detail so as to process embodying-my invention. i

1 will'now proceed to describe the process of treating thepetroleum oils with hydroxids of the alkali metal group and hydrogen sulfid, this treatment being particularly applicable, but not necessarily confined to paraffin wax, kerosene oil, and White paraffin oil for medicinal use, and I will 'describe the invention for the sake of illu'stration for the removalof elementary sulfur from partially finished white medicinal oil.

Previous to treatment this oil may contain .03 per cent. sulfur, of whichfl02 per cent. is elementary sulfur and .01 per cent. is in the form of inodorous sulfur, not elementary, and in this form unobjectionable 'in oils for the, use stated and contained in sulfur compounds left after treatment with sulfuric acid, said oil being pumped into tures, and rapidly at higher temperatures, and, if the temperature is too low, the opera.-

tion will-become too tedious, and, if on the other hand, the temperature is too high, the oil may become scorched, giving rise to objectionable odor and taste. I prefer to employ a temperature between F. and

R, which temperature will usually be reached within an hour after steam is first admitted to the heating coil, but the time depends largely upon the area of the heating coil. I

While the preliminary heating of the oil is going on, the chemicals used in the treatment of the sulfur-bearing oil may be mixed the tank 6, and for this purpose, I preferably employ the following proportions,

which I have found give excellent results, but it will be understood that they may be varied as conditions and qualities of the oil may require, or may be deemed expedient, without departing from the spirit of my invention.

To 158 pounds of caustic soda is added 458 pounds of water to form a solution. The caustic soda not only unites with the hydrogen sulfid, in'the manner hereinafter de-- scribed, to form sodium sulfid, but. the caustic soda also goes to (l) neutralize any acid water is added, the difliculty of getting a and is discharged from the latter throughthorough incorporation of oil and the treating solution is increased.

When the oil has been raised to the proper temperature, namely, a temperature of 160 F. to 190 F., the solution of caustic sodais injected into the oil Within the cylinder. In order to accomplish this, the chemical is drawn through the pipes 7 to the pump 8.

the pipes 10 and 11, and perforated spray nozzle 12, into the oil. "'It'is important, al-

though not essential, to have the chemical in the pipes 10, 11, and spray nozzle 12 under pressure which will be .continuous through saidpipes up to the perforations in the nozzle, so that the jets of the chemical issuing from the latter will strike the oil with considerable force, and effect a thor-' ough mingling of the oil and the chemical solution.

The chemical solution injected into the oil in the manner described, will graduallyfind its way by gravity through the body of oil to the bottom of the agitator, and during the initial treatment, I maintain the valves 13 5 and 17 closed, so that the solution will accumulate in the bottom of the agitator,

an'd'the pumping is continued until all, or

the desired amount, is drawn from thepipe 6 and injected into the agitator. When the desired amount of chemical solution has been fed to the oil, the valves '13 and 14 are opened, and the valves 5, 9 and 17 closed, and the pump is then operated to circulate the solution through the body of oil being treated, the pipe 13, the pump, the pipes 10, 11, and spray nozzle 12. At the same time the valve 30 in the pipe 30 is opened, and

hydrogen sulfid introduced to the oil. During this circulation, the sodiumhydroxid and the hydrogen sulfid are brought into intimate contact, and form sodium sulfid, which in turn, reacts upon the elementary sulfur present in. the oil to form higher sulfids of the sodium. In carrying out the f process, the amount of elementary sulfur present in the oil should first be determined by analysis, and sufficient sodium hydroXid should be added to the oil, so that when the is injected into the oil, the sodium sulfid so formed, will react with, and eliminate all of the elementary sulfur from the oil. During same reacts with the hydrogen sulfid which vI this circulation, the temperature of the oil being treated is maintained by means of the coil 24:, at a temperature of from approximately 160 F. to approximately 190 F.

During the treatment described, test, samples of the oil aretaken from time to'time,

said samples being washed with water and filtered through filter paper to remove the last tracesof moisture, and are then placed in a test glass with a piece 'of bright copper, -and heated to about 175 F. for about one hour. When the test samples cease to show i 7 any discoloration or tarnishing of the copper, this stage ofthe process is-considered finished. It may require from one to three hours, because the solution seems to be more; actlve sometimes than at others, for some reason I havebeen unable to ascertain.

When the testfsample's cease to discolor the copper, as above described, the chemical solution is allowed to settle in the conical bottom of the vessel, and the settling is continued fora period of from six to ten hours in order to insure all of the solution being separated from the treated oil. When the maximum separation of the solution is assured by adequate settling, the solution may be drawn off from the vessel and returned to i the tank 6 through thepipe 4E, the pipe 15, and the'discharge lfi, and said solution resei'ved for further use in the treatment of 01 I then treat be suspended in the oil. I prefer to accomthe oil to remove therefrom any'residual alkaline sulfid which may still plish this by treating the oil with'what is known as a still wash either'by playing water from a hand-hose, ontov the surface of the oil, drawing the water off continu- .ously at the bottom of the vessel as the watermay. settle, or the water may be applied by pumping it through a permanent spray pipe- S arranged .at the top of the cylinder. This treatment may be followed up by an injection of live steam through the pipes 18, 19. This washing process, in-

, cluding the water wash andthe steam, may

extend over a periodof four hours, but may be done in less or greater time, according to circumstances. Instead of injecting live steam from a boiler into the base of the receptacle, I may pump-clear, pure water into the bottom of the receptacle and generate steam therefrom, while in direct contact with the oil by means of a heating coil 24L similar to the coil 24. This latter method is sometimes preferable because ordinary boilersteam may contain impurities Which will be detrimental to the oil being treated. The oil is then allowed to stand for about ten to twelve hours and the water is carefully drawn oif and discharged to any suitable point, as, for instance, a sewer, through the pipe 4:. It may be that the treated oil still shows a cloud of moisture, but this may be refnoved by cutting off the steam flowing through the pipes 18, 19, and injecting air from the pipe 20 into the pipes 18 and 19,and into the body of ,oil. This step of the process may continue fora period of from approximately one to approximately three hours, whereupon the oil is usually found bright, and is considered finished. I

In Fig. 2I have shown an apparatus suitable for carrying out the process embodying my invention when a hydroxid of an alkaline earth metal and hydrogen sulfidare to be used inthe treatment of the oil.

The apparatus here shown, is the same as that shown in Fig. 1, with the exception that the pump 8, and the connections associated therewith, namely, the tank 6, pipes 7, 13, 10, 11 and 12, for introducing the chemicals to the oil, are dispensed with,-

since the alkaline earth sulfids which are used in solid form, may be introduced to the oil, for example through the explosion doors 31. Furthermore, the device for introducing water into the oil for washing the same, is unnecessary when the, hydroxids of the alkaline earth metals and hydrogen sulfid are used. Furthermore, the process is preferably carried out at a term perature higher than that at which the process using a hydroxid of an alkali metal is carried out, and for the purpose of bringing the metal to the desired temperature, heating coils 24 and 24 are provided at their free ends with valves 26 and24", respectively, which are opened during the heating process just suflicient to permit the condensed water to drain from the device.v

-The pipe 30, which extends a short dismeager any suitable source, the pipe being provided with a suitable valve 30.

' Material suitable for carrying out the process with a hydroxid of an alkaline earth metal may be prepared as follows 800 pounds of freshly burned lime may be placed in an open pan or receptacle, into which ispoured 50 gallons of Water, the amount of water added being just sufiicient to leave the lime in the proper physical condition, neither dusty nor pasty. The oil is first heated to the desired temperature, preferably to a temperature above the condensing ,point of water, and at a temperature ranging from 212 F. to 300 F.

The heating operation is carried out by,

means of the heating coils 24: and 24?, the parts 26 and 24" being open sufficiently to permit the condensed water to escapef When the oil has reached the desired temperature, the slaked lime is introduced to the oil in any desired manner, and steam tnen permitted to pass into the oil through the pipe 19, and thus agitate the oil and bringthe hydroxid of the alkaline earth into thorough contact with the hydrogen sulfid, and reacts therewith to form an alkaline earth sulfid. The sulfid in turn reacts with the elementary sulphur present in the oil and forms therewith higher sulfids, and thus eliminates the elementary sulfur from the oil. After the oilhas been thoroughly agitated with the calcium hydroxid, the oil "is permitted to settle, and the settling will usually require about six hours.- The oil is then tested with copperto determine a whether all of the elementary sulfur has been eliminated, and if elementary sulfur -sulfur from petroleum oil,.which consists in treating said oil with an alkaline hydroxid and hydrogen sulfid, and continuing the treatment until the treated oil ceases to have a darkening eifect on metallic copper.

3. The process .of removing elementary sulfur from petroleum oil, whichconsists in treating said oil with an alkaline hydroxid and with hydrogen sulfidaccompanied by heat at a temperature of from F. to F. I j

4. The process of. removing elementary sulfur from petroleum oil, which consistsan treating said oil with an alkaline hydroxid and hydrogen sulfid under alkaline conditions.

i 5. The process of removing elementary sulfur from petroleum'oil, which consists in treating said oil With a solution of an alka-v line h droxid and hydrogen sulfid.

6. he process of removing elementary sulfur from petroleum oil, which consists in treating said oil with a solution of analkaline hydroxid and hydrogen sulfid, and circulating said solution through the body of petroleum oil. a

7. The process of. removing elementary sulfur from petroleum oil, which consists in treating said oil with a solution of an alkaline hydroxid and hydrogen sulfid, and circulating said solution through the body of petroleum oil until the treated oil ceases to have a darkening effect on metallic copper.

8. The process of removing elementary sulfur from petroleum oil, which consists in treating said oil with a solution of sodium hydroxid in the proportion of about 158 parts by weight of caustic soda and 458 parts by weight of Water and with hydrogen sulfid. I

9. The process of removing elementary sulfur from petroleum oil, which consists in heating said oil for approximately one hour, treating the same with a solution of an alkaline, hydroxid and hydrogen sulfid for from approximately one hour to approximately three hours, separating the sulfid resulting from the treatment from the oil, and aftertreating the oil' to remove residual sulfi suspended in the oil.

10. The process of removing elementary sulfur from petroleum oil, which consists in approximately one hour to approximately three hours, while maintaining the same at a temperature offrom about 160 F. to 190 F., separating the sulfid so formed from the oil, and after-treating the oil to removeresidual sulfid suspended in the oil.

11. The process 'of removing elementary sulfur from petroleum oil, which consists in heating said oil to a temperature of from about 160 F. to 190 F., treating the same with a solution of an alkaline hydroxid and hydrogen sulfid, separating the sulfid formed by the treatment from the oil, and after-treating the oil to remove residual sulfid suspended in the oil.

12. The process of removing elementary sulfur from petroleum oil, which consists in treating-said 'oil with an alkaline hydroxid and hydrogen sulfid accompanied by agitation.

13. The process of removing elementary sulfur from petroleum oil, which consists in treating said oil Withan alkaline hydroxid and hydrogen sulfid accompanied by agitation and heat.

In testimony whereof I have hereunto signed my name in the presence of two subscribing witnesses.

ERNEST B. COBB.

Witnesses:

ADELE S. EBERHARDT, DANN L. W001). 

